Non-volatile memory systems, such as flash memory, have been widely adopted for use in consumer products. Flash memory may be found in different forms, for example in the form of a portable memory card that can be carried between host devices or as a solid state disk (SSD) embedded in a host device.
As the non-volatile memory cell scales to smaller dimensions with higher capacity per unit area, the cell endurance due to program and erase cycling, and disturbances (e.g. due to either read or program) may become more prominent. The defect level during the silicon process may become elevated as the cell dimension shrinks and process complexity increases. Accordingly, memory meeting high endurance requirements may be more difficult, which may further increase research and development costs for the technology scaling.
Memory undergoes write/erase cycles due to both host writes and non-host writes. Non-host writes may include memory maintenance and/or background operations performed by/on the memory card. The memory recycling due to this memory maintenance may significantly reduce the card life. Memory maintenance may be performed whenever there is idle time and certain solutions attempt to reduce the number of write/erase cycles due to memory maintenance.